Make CommandBuffer::Flush asynchronous, and add CommandBuffer::FlushSync with former semantics.

gpu/command_buffer/client/cmd_buffer_helper.h

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file contains the command buffer helper class.
 
 #ifndef GPU_COMMAND_BUFFER_CLIENT_CMD_BUFFER_HELPER_H_
 #define GPU_COMMAND_BUFFER_CLIENT_CMD_BUFFER_HELPER_H_
 
 #include <string.h>
@@ skipping 24 matching lines @@
  public:
   explicit CommandBufferHelper(CommandBuffer* command_buffer);
   virtual ~CommandBufferHelper();
 
   // Initializes the CommandBufferHelper.
   // Parameters:
   //   ring_buffer_size: The size of the ring buffer portion of the command
   //       buffer.
   bool Initialize(int32 ring_buffer_size);
 
+  // Asynchronously flushes the commands, setting the put pointer to let the
+  // buffer interface know that new commands have been added. After a flush
+  // returns, the command buffer service is aware of all pending commands.
+  void Flush();
+
   // Flushes the commands, setting the put pointer to let the buffer interface
   // know that new commands have been added. After a flush returns, the command
   // buffer service is aware of all pending commands and it is guaranteed to
   // have made some progress in processing them. Returns whether the flush was
   // successful. The flush will fail if the command buffer service has
   // disconnected.
-  bool Flush();
+  bool FlushSync();
 
   // Waits until all the commands have been executed. Returns whether it
   // was successful. The function will fail if the command buffer service has
   // disconnected.
   bool Finish();
 
   // Waits until a given number of available entries are available.
   // Parameters:
   //   count: number of entries needed. This value must be at most
   //     the size of the buffer minus one.
@@ skipping 156 matching lines @@
 
   CommandBuffer* command_buffer_;
   Buffer ring_buffer_;
   CommandBufferEntry *entries_;
   int32 total_entry_count_;  // the total number of entries
   int32 usable_entry_count_;  // the usable number (ie, minus space for jump)
   int32 token_;
   int32 last_token_read_;
   int32 get_;
   int32 put_;
+  int32 last_put_sent_;
 
   friend class CommandBufferHelperTest;
   DISALLOW_COPY_AND_ASSIGN(CommandBufferHelper);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_CLIENT_CMD_BUFFER_HELPER_H_